Hammer for impact pulverizer



-April 19, 1949. F. E, SM TH 2,467,865

HAMMER FOR IMPACT PULVERIZERS Filed May 3, 1944 2 Sheets-Sheet 1 3 April19, 1949.

F. E. SMITH HAMMER FOR IMPACT PULVERIZERS Filed May}, 1944 2Sheets-Sheet 2 Patented Apr. 19, 1949 Application May 3, 1944, SerialNo. 533,351 -1 Claim. (01. 241 19v)' l The present invention relatesgenerally to improvements in rotary impact crushers or pulverizers, andhas particular reference to improvements in the revolving hammersadapted for use therein.

Pulverizing hammers of the type disclosed in my prior Patent No.2,152,332 are provided with a replaceable wear tip which is reversiblyand re movably connected to the outer end of the hammer arm, and whichhas oppositely disposed impact faces formed with marginal corners oredges that extend transversely of the path of movement for impact withthe incoming material to be pulverized. These impact corners or edgesare adapted to be disposed individually in a1ead ing or working positionat the extreme outer end of the hammer upon securing the tip thereto indifferent selective positions of assembly. When the arm and the tip aresymmetrically arranged relative to the longitudinal center line of thehammer, as has been the practice heretofore, the two outermost impactedges are equidistant from the axis of revolution and are locatedrespectively in leading and trailing positions. Consequently, as wearoccurs in use, the leading edge will recede and after a certain amountof such recession, the trailing edge will also come into contactwith thematerial being pulverized and hence into the line of wear. It is,therefore, desirable, in order to obtain full and uniform wear on allimpact edges of the replaceable tip, that the tip be reversed frequentlyand at proper times back and forth into its different selectivepositions on the hammer arm. Such reversal of necessity requires.

frequent attention, and involves inconvenience and loss ofproduction'time.

The primary object of the present invention is to provide a novelpulverizing hammer, having a plurality of selectively available impactcorners or edges which willbe eflicient and comparatively long-lived inuse, and which in particular will permit each of the impact edges to beworn out completely.

Another object is to provide anew and improved pulverizing ham-merhaving areversible. tip which is removably connected to the hammer armin such a manner that when any one of a plurality of impact corners oredges is located for use in working position, it alone will be subjectto Wear until completely worn out, while the other edge or edges will bespaced inwardly away from the line of wear.

A further object is to provide a novel pulver izing hammer having an armand a replaceable tip in which the tip is so mounted that the center ofgravity is located in advance of the center line of the arm, whereby toproject one impact edge out-, wardly radially beyond the other edge oredges.

A general object is to provide a new and improved pulverizer hammerwhich is simple and inexpensive to manufacture, which permits of amaximum amount of Wear with a minimum loss of scrap metal when the tipis replaced, and which requires little attention in use and adjustmentof the tip only after each edge is completely worn out. I

Other objects and advantages will become apparent as the descriptionproceeds.

In the accompanying drawings,

Figure 1 is a. side elevational view of an impact hammer with afour-corner tip embodying the features of my invention.

A Fig. 2 is anenlarged perspective view illustrat ing the arm and tip ofthe hammer in disassembled relation.

Fig. 3 is a side elevational view of a modified form of hammer with atwo-corner tip.

Fig. 4 is a. front face view of the hammer shown in Fig. 3.

Fig. 5 is a sectional view taken along the line 5-5 of Fig. 3.

Fig. 6 is a transverse vertical sectional view of a pulverizer providedwith impact hammers embodying the features of my invention.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawings and will hereindescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific formdisclosed, .but intend to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asexpressed in the appended claim.

Referring"more panticularly to the drawings,

impact hammers embodying the present invention are adapted for use invarious types and kinds of crushers vor pulverizers, and for purposes ofillustration one form of hammer is shown in connection with a rotarypulverizer of con for the material, such as stone, to be crushedorpulverized. Suitably mounted in the casing l0 is a drive shaft 13adapted to be connected toxa source of power (not shown).. Hammer.suspension means is mounted on the shaft I 3,-

and in the present instance comprises a plurality otaxially spaced disksl4 (one shown) se 3 cured in fixed relation to the shaft. A plurality ofhammers l5, four in the present instance, are suitably secured inuniformly peripherally spaced relation to the disks l4 and projectradially there from. The casing II] is provided in the top por-,

"tion with a liner plate Hi and in the bottom with a grate structure U,conforming generally to the circle of revolution of the hammers l5.

It will be understood. that inusethe, hammers are revolved at very; highspeeds; Hence, they are subjected to heavy centrifugal force and also tosevere impact in reducing the material to be. pulverized. Wear occurs atthe outer leading edges of the hammer tips, and necessitates fre 'quentreplacement of the hammers.

The primary feature of the present, invention resides in the provisionof animpact hammerhaving a replaceable tip with a plurality of im- Ipact corners or edges which can be easily and quickly reversed to permitsuccessive use orall the impact edges before, requiring replacement; andwhich in difierentpositions; of,adjustment, willf subject only theactive edge to.wearthrough contact with the material being pulverized.

Referring first to the form of Figs. 1 and 2, the hammerconstituting oneexemplary embodiment of the invention com-prisesa pivotal-suspensionmember which maybe of any suitab-le'type', and which is shownas. aflat-sided hammer arm. l8 adapted to be pivotally connected at one endto the disks M for swinging movement. Intl'le present instance, theinner end of the arm I 8. is formed with an opening 19 adapted't'oreceive a supporting shaft 20 anchored'ilto the disks. l4 and extendingthrough the intervening space, in. parallel relation .to the shaft [3.In operation, centrifugal force will causethe arm [,8 normally to occupya generally radialipositionjwith refer-. ence to the axis of revolution.

A. replaceable wear tip. 2| is reversibly secured to the other or outerend of the arm I28; and. is removably; connected thereto. by a strongjoint. The tip 2| is provided with a plurality of spaced. impact edges.which extend transversely of the path of revolution, and which are,adapted; to, be located. singly in active position, by selectivereversal of the tip onthearm l8; In the par? ticular form shown, the tip21 is generally rec-.- tangular in cross section and is formed withfront and rear impact faces 22 and23. The four. transverse corners A, B,C and D, which extenclalOng. and define the margins of the impact faces.22 and 23, constitute the impactedges. These edges. are comparativelysharp at the start, but as they wear in use will recede and become.rounded'valon the line of wear 24. Pref'era'bly,.the.impactfaces. 22and. 23' are slightly hollow V-shaped'.,

The tip 2| is supported'on the arml.8',in.such. a manner that only oneof theimpactedgesata time wil be located in active or working position.-to; strike the materialbeing pulverized. Asa re.- sult, the inactiveedges. will be maintained. out; of" contact withthe-material, and. wear.wlllbe. con.- fined to the active edge.

Selective location of theimpactedges singly. in. active position, isaccomplished by mountingthe; tip 2! on the front-or leading side of. thearm. l8,. whereby the center. ofgravityH of thehammer islocated onaradial line, h-h throughthe axes of.

the shafts l3 and 20 eccentrically. to. and in ade 70 the tip can bereverse-d for exam'file Side for vance of; the longitudinal center linea -a and center-of'gravity A of the arm 18, and trailing the center ofgravity T of the tip 2| on the radialline' t--t through the axis of theshaft; More-par ticularly; one orthe other-of the impact-faces 2'2 7'5active position, and finally upon reversal side for and 23 is seatedagainst a complemental mounting surface 25 on the front of a cross head26 integral with the outer end of the arm 18. With the tip 2! somounted, two of the impact edges, for example the edges A and B, arelocated in a leading position, and the other two edges, for example theedges C and D, are located in a trailing position. The outermost leadingedge, for example the edge A, is disposed inz-active position to. strikethe material being pulverized, and in use is subject to wear down to theline of wear 24. By reason of the eccentricity of the center of gravity,the four-corner tip Zl will occupy a forward-1y and outwardly inclinedposition so that the outermost trailing edge, for example the edge D, iscaused to move through a reduced circle of revolution well within theline 24 and, therefore, out-0f striking contact with the material.Obviously, the innermost impact edges 13 and C are spaced radiallyinwardly from. the outermost edges A and C. and, therefore, are alsoout. of: striking contact with thematerial.

The joint for positively locating and: connect? ing the tip 2| indifferent selective positions to: the arm l8 comprises twospaced keysorlugs 21 projecting forwardly from-opposite side areas-of; the mountingsurface 25, and adapted to be re. ceived in complemental recesses; 0rgrooves; formed in opposite sides of the tip. The grooves; 28. open toboth impact faces 22- and2r3: so that: the lugs 2'! will engage inoneend or the: other; thereby permitting reversal of the tip front. for;rear to locateeither the edges A and, B orrther edges'C and Din theforemost or'leading position.. The grooves also arelocatedsymmetricallyacross: the sides of the tip 2i so that the lattercanbm reversed side for side to locate either'the edges; A and D or Band C in the outermost position... Preferably, the lugs 2'! are tapered,and the.op.--

posite ends of thegrooves 28 are correspondingly:

flared to obtain close wedge engagement:

As. an. additional locating and interlocking: means, the head. 26 isprovided with'an intermet diate square lug'or projection 29 between thelugs 21 and adapted tobe received in either of two: complementalopenings Bilwhich are formed cen-- trally in the respective impact faces22 and 23 and separated by an intermediate wall or web 3-1. To securethe tip in position of assembly, a bolt: 32 is adapted to be insertedthrough a hole 33in the web 3i and an alined bore 34 opening throughthe. square 1'ug29 and the head 26, and tobe' tightened by a nutthreadedthereon against the rear face of the arm l8.

In operation, and assuming that the tip 2! isinitially secured inposition of assembly with one of the impact edges, for example the edgeA, disposed in the outermost leading position for strik ingengagementwith the material being pulverized, centrifugal force will" cause thetip to as sume a position inclinedto the radius of revolution, with theactive edge A describing a maxi mum circle of revolution. The other"impact edges B, C, and D will describe lesser circles of revolution, andhence remain out of striking contact-with the material. Upon continueduse; the edge A will be worn away down to the line 2'4, and; when theedge has been completely worn down,.

side, to dispose the other impact edgeB' of the.

face 22 inactive position. When the secondedge B has been completelyworn down, the tip can be reversed front for rear to'dispose the edgeC'in.

side the edge D can be disposed in active position.

Figs. 3, 4 and 5 illustrate a modified form of the invention having atwo-corner replaceable tip 20*. The construction is generally similar tothat of the hammer with the four-comer tip, and corresponding partsthereof are identified by the same reference numerals as in the firstform, plus the letter a. In this form, the tip 2| has a rear surface 23adapted to seat against the front surface 25- of the head 26, and hasonly one impact face 22* with transverse marginal corners or impactedges E and F. The surfaces 23 and 25 are fiat and located substantiallyin an axial plane through the shaft 20. The tip Zi is not reversiblefront for rear and, hence, the recesses 28 do not extend to the face 22The lugs 2'! of the joint are tapered on such an angle that theoutermost inclined sides thereof are substantially parallel to the lineof wear 24*, thereby making availabl a maximum amount of stock to beworn away at each corner. In this form, as in the form of Figs. 1 and 6,the tip 21a has a center of gravity T on a radial line tt' through theaxis of the hole l9a, and the arm l8a has a center of gravity A on aradial line a'a also through the axis of the hole l9a, and the hammerincluding the arm Mia and eccentrically mounted tip 2la has a center ofgravity H intermediate the centers of gravity T' and A on at radial lineh-h' extending through the axes of the opening I 9a and the shaft 13when the hammer is subjected to centrifugal force.

It will be evident that I have provided a new and improved impact hammerwhich has a plurality of impact corners or edges adapted to be used oneafter another until completely worn out, and in which none of thecorners excepting the one located in active position is subject to wear.As a result, all corners of the hammer can be fully worn down inperforming useful work and to leave a minimum of stock to be discardedwhen the tip is replaced. Frequent reversal of the tip is unnecessary sothat undue loss of production time is avoided.

I claim as my invention:

An impact hammer for rotary pulverizers comprising, in combination, ahammer arm adapted to be supported at one end and having, a cross headon the other end with a mounting surface on the leading side, twoforwardly projecting wedge lugs extending in spaced relation fromoposite ends of said surface, and an intermediate lug extendingforwardly from said surface between said wedge lugs, a four-sided hammertip having front and rear faces adapted to be seated directly againstsaid surface and having four transverse corners defining impact edges atthe inner and outer margins of said faces, said tip being formed inopposite ends with transverse grooves flared outwardly in each directionfrom an intermediate point and adapted to interfit selectively with saidwedge lugs and being formed in said faces with openings separated by anintermediate web and adapted to interfit and receive said intermediatelug, said tip being reversible on said surface side for side and frontfor rear to present any one of said four corners in an outermost forwardworking position, and being located in advance of and spaced from thecenter line of said arm, whereby to cause the trailing outermost cornerto have a lesser circle of revolution than the forward outermost corner,and a clamping bolt adapted to be extended through said web and saidintermediate lug for removably securing said tip to said head inselected position of adjustment.

FORREST E. SMITH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,085,692 Liggett Feb. 3, 19 141,424,225 Williams Aug. 1, 1922 1,434,540 Hiller Nov. 7, 1922 1,476,177Plaisted Dec. 4, 1923 1,562,048 Plaisted Nov, 17, 1925 1,630,021 LucasMay 24, 1927 1,655,238 Plaisted Jan. 3, 1928 1,693,058 Shelton Nov. 27,1928 2,152,332 Smith Mar. 28, 1939 2,331,597 Coles Oct. 12, 1943 FOREIGNPATENTS Number Country Date 660,974 France Feb. 26, 1929 r 475,430 GreatBritain Nov. 19, 1937

